[PATCH 3/3 v2] clocksource/drivers/fttmr010: Just count down
From: Linus Walleij
Date: Wed Sep 22 2021 - 15:59:33 EST
All timers can handled just counting down so what about just
doing that instead of special-casing the counting down mode.
This has the upside that overflow cannot occur so we can
remove some handling of that interrupt as well.
Cc: Cédric Le Goater <clg@xxxxxxxx>
Cc: Joel Stanley <joel@xxxxxxxxx>
Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
---
ChangeLog v1->v2:
- New patch.
---
drivers/clocksource/timer-fttmr010.c | 97 +++++-----------------------
1 file changed, 16 insertions(+), 81 deletions(-)
diff --git a/drivers/clocksource/timer-fttmr010.c b/drivers/clocksource/timer-fttmr010.c
index 5af8ea388cc4..f72ec84884e2 100644
--- a/drivers/clocksource/timer-fttmr010.c
+++ b/drivers/clocksource/timer-fttmr010.c
@@ -119,21 +119,11 @@ static inline struct fttmr010 *to_fttmr010(struct clock_event_device *evt)
return container_of(evt, struct fttmr010, clkevt);
}
-static unsigned long fttmr010_read_current_timer_up(void)
-{
- return readl(local_fttmr->base + TIMER2_COUNT);
-}
-
static unsigned long fttmr010_read_current_timer_down(void)
{
return ~readl(local_fttmr->base + TIMER2_COUNT);
}
-static u64 notrace fttmr010_read_sched_clock_up(void)
-{
- return fttmr010_read_current_timer_up();
-}
-
static u64 notrace fttmr010_read_sched_clock_down(void)
{
return fttmr010_read_current_timer_down();
@@ -148,17 +138,7 @@ static int fttmr010_timer_set_next_event(unsigned long cycles,
/* Stop */
fttmr010->timer_shutdown(evt);
- if (fttmr010->is_aspeed) {
- /*
- * ASPEED Timer Controller will load TIMER1_LOAD register
- * into TIMER1_COUNT register when the timer is re-enabled.
- */
- writel(cycles, fttmr010->base + TIMER1_LOAD);
- } else {
- /* Setup the match register forward in time */
- cr = readl(fttmr010->base + TIMER1_COUNT);
- writel(cr + cycles, fttmr010->base + TIMER1_MATCH1);
- }
+ writel(cycles, fttmr010->base + TIMER1_LOAD);
/* Start */
cr = readl(fttmr010->base + TIMER_CR);
@@ -194,24 +174,11 @@ static int fttmr010_timer_shutdown(struct clock_event_device *evt)
static int fttmr010_timer_set_oneshot(struct clock_event_device *evt)
{
struct fttmr010 *fttmr010 = to_fttmr010(evt);
- u32 cr;
/* Stop */
fttmr010->timer_shutdown(evt);
-
- /* Setup counter start from 0 or ~0 */
writel(0, fttmr010->base + TIMER1_COUNT);
- if (fttmr010->is_aspeed) {
- writel(~0, fttmr010->base + TIMER1_LOAD);
- } else {
- writel(0, fttmr010->base + TIMER1_LOAD);
-
- /* Enable interrupt */
- cr = readl(fttmr010->base + TIMER_INTR_MASK);
- cr &= ~(TIMER_1_INT_OVERFLOW | TIMER_1_INT_MATCH2);
- cr |= TIMER_1_INT_MATCH1;
- writel(cr, fttmr010->base + TIMER_INTR_MASK);
- }
+ writel(~0, fttmr010->base + TIMER1_LOAD);
return 0;
}
@@ -226,19 +193,7 @@ static int fttmr010_timer_set_periodic(struct clock_event_device *evt)
fttmr010->timer_shutdown(evt);
/* Setup timer to fire at 1/HZ intervals. */
- if (fttmr010->is_aspeed) {
- writel(period, fttmr010->base + TIMER1_LOAD);
- } else {
- cr = 0xffffffff - (period - 1);
- writel(cr, fttmr010->base + TIMER1_COUNT);
- writel(cr, fttmr010->base + TIMER1_LOAD);
-
- /* Enable interrupt on overflow */
- cr = readl(fttmr010->base + TIMER_INTR_MASK);
- cr &= ~(TIMER_1_INT_MATCH1 | TIMER_1_INT_MATCH2);
- cr |= TIMER_1_INT_OVERFLOW;
- writel(cr, fttmr010->base + TIMER_INTR_MASK);
- }
+ writel(period, fttmr010->base + TIMER1_LOAD);
/* Start the timer */
cr = readl(fttmr010->base + TIMER_CR);
@@ -268,7 +223,7 @@ static irqreturn_t fttmr010_timer_interrupt(int irq, void *dev_id)
}
val = readl(fttmr010->base + TIMER_INTR_STATE);
- if (val & (TIMER_1_INT_MATCH1 | TIMER_1_INT_OVERFLOW))
+ if (val & TIMER_1_INT_MATCH1)
evt->event_handler(evt);
else
/* Spurious IRQ */
@@ -284,9 +239,8 @@ static irqreturn_t ast2600_timer_interrupt(int irq, void *dev_id)
u32 val;
val = readl(fttmr010->base + TIMER_INTR_STATE);
- if (val & (TIMER_1_INT_MATCH1 | TIMER_1_INT_OVERFLOW)) {
- writel(TIMER_1_INT_MATCH1 | TIMER_1_INT_OVERFLOW,
- fttmr010->base + TIMER_INTR_STATE);
+ if (val & TIMER_1_INT_MATCH1) {
+ writel(TIMER_1_INT_MATCH1, fttmr010->base + TIMER_INTR_STATE);
evt->event_handler(evt);
} else {
/* Just clear any spurious IRQs from the block */
@@ -360,15 +314,10 @@ static int __init fttmr010_common_init(struct device_node *np,
writel(0, fttmr010->base + TIMER_INTR_STATE);
}
- /*
- * Enable timer 1 count up, timer 2 count up, except on Aspeed,
- * where everything just counts down.
- */
if (is_aspeed)
val = TIMER_2_CR_ASPEED_ENABLE;
else {
- val = TIMER_2_CR_ENABLE | TIMER_1_CR_UPDOWN |
- TIMER_2_CR_UPDOWN;
+ val = TIMER_2_CR_ENABLE;
}
writel(val, fttmr010->base + TIMER_CR);
@@ -381,23 +330,13 @@ static int __init fttmr010_common_init(struct device_node *np,
writel(0, fttmr010->base + TIMER2_MATCH1);
writel(0, fttmr010->base + TIMER2_MATCH2);
- if (fttmr010->is_aspeed) {
- writel(~0, fttmr010->base + TIMER2_LOAD);
- clocksource_mmio_init(fttmr010->base + TIMER2_COUNT,
- "FTTMR010-TIMER2",
- fttmr010->tick_rate,
- 300, 32, clocksource_mmio_readl_down);
- sched_clock_register(fttmr010_read_sched_clock_down, 32,
- fttmr010->tick_rate);
- } else {
- writel(0, fttmr010->base + TIMER2_LOAD);
- clocksource_mmio_init(fttmr010->base + TIMER2_COUNT,
- "FTTMR010-TIMER2",
- fttmr010->tick_rate,
- 300, 32, clocksource_mmio_readl_up);
- sched_clock_register(fttmr010_read_sched_clock_up, 32,
- fttmr010->tick_rate);
- }
+ writel(~0, fttmr010->base + TIMER2_LOAD);
+ clocksource_mmio_init(fttmr010->base + TIMER2_COUNT,
+ "FTTMR010-TIMER2",
+ fttmr010->tick_rate,
+ 300, 32, clocksource_mmio_readl_down);
+ sched_clock_register(fttmr010_read_sched_clock_down, 32,
+ fttmr010->tick_rate);
/*
* Setup clockevent timer (interrupt-driven) on timer 1.
@@ -441,12 +380,8 @@ static int __init fttmr010_common_init(struct device_node *np,
#ifdef CONFIG_ARM
/* Also use this timer for delays */
- if (fttmr010->is_aspeed)
- fttmr010->delay_timer.read_current_timer =
- fttmr010_read_current_timer_down;
- else
- fttmr010->delay_timer.read_current_timer =
- fttmr010_read_current_timer_up;
+ fttmr010->delay_timer.read_current_timer =
+ fttmr010_read_current_timer_down;
fttmr010->delay_timer.freq = fttmr010->tick_rate;
register_current_timer_delay(&fttmr010->delay_timer);
#endif
--
2.31.1